Circuit breaker



Dec. 17, 1940. J. G. SOLA 2,224,885

CIRCUIT BREAKER vFiled Oct. 18, 1937 \NSULATION lmsuLATxpu Z5 PatentedDec. 17, 1940 UNITED STATES CIRCUIT BREAKER Joseph G. Soia, Oak Park,Ill., assignor to Sola Electric 00., Chicago, 111., a corporation ofDelaware Application October 18, 1937, Serial No. 169,578

7 Claims.

My invention relates to circuit breakers of a type adapted to open .anelectric circuit in case of an objectionable overload condition therein,

and it has for its object the provision of a new and improved form andarrangement of parts whereby one set of parts is effective for openingthe circuit upon a heavy surge of current such as is established by ashort circuit and another combination of parts is effective for openingthe circuit when a moderately excessive current is carried thereby.Means is preferably provided in either case to maintain the circuit inopen condition until the short-circuit or other overload has beencorrected, the arrangement to be such that, when the circuit is openedindependently of the circuit breaker after the abnormal condition hasbeen corrected, the circuit through the breaker mechanism isautomatically reestablished for renewed operation.

It is one of the objects of my invention to provide an improvedarrangement for accomplishing the above mentioned results by the use ofan electromagnet and a switch connected in series with the armature ofthe magnet in such relation that upon a surge of current through themagnet the switch is opened by the movement of the armature for breakingthe circuit through the coil, a second coil being provided on the coreof said magnet connected in the circuit in parallel arranger'nent withrespect to the switch so as to be short-circuited when the switch isclosed, said second coil when energized being adapted to move thearmature to the limit of, its motion toward the magnet so as to open theswitch completely and to hold it open until the circuit through themagnet has been broken independently of the switch.

It is one of the objects of my invention to provide in a device of thistype an arrangement of parts whereby said switch may be openedindependently of movement of the armature upon the passage of anoverload current through the switch so as to throw said second coileffectively into operation for movement of the armature toward themagnet, such independent opening of the switch being effected preferablyby thermostatic action due to the heating of a conductor part when suchoverload occurs.

It is one of the objects of my invention to provide an improvedarrangement of stop means for the switch, comprising an arm in positionto limit the movement of the armature in the direction for closing theswitch, said arm being located in close proximity to the contacts of theswitch at the point where they engage each other so as to be adapted toreceive and carry away a great part of the heat generated by the sparkproduced by the current on the opening of the switch.

It is another object of my invention to improve devices of this type insundry details hereinafter pointed out. The preferred means by which Ihave accomplished my several objects are illustrated in the drawing andare hereinafter specifically described. That which I believe to be newand desire to cover by Letters'Patent is set forth in the claims.

In the 'drawing-- Fig. 1 is a side view of the preferred form of myimproved circuit breaker;

Fig. 2 is a top plan view of the device shown in Fig. 1;

Fig. 3 is a view similar to Fig. l but on an enlarged scale with thecircuits and connections shown diagrammatically;

Fig. 4 is a view similar to the top portion of Fig. 3 but with certainof the parts in changed position; l

Fig. 5 is a horizontal sectional view taken at line 5-5 of Fig. 4; and

Fig. 6 is a schematic view showing the wiring connections. 4

Referring now to the several figures of the drawing in whichcorresponding parts are indicated by the same reference characters, inindicates a base memberv formed of insulating material, with a metallicstandard II connected therewith and rising therefrom, the standard inthe arrangement shown being mounted in position by means of a baseportion I2. Upon the base l2 of the standar d l I I have mounted a blockI 3 of insulation material upon which in turn I have mounted a framemember H in the form of a U, such frame member I comprising standards l5and i6 being formed of iron or other suitable magnetic material. Uponthe base of the U member Hi I have mounted a core member I! upon whichare mounted two coils l8 and [9. Upon the upper end of the standard I6,I have pivotaliy mounted an armature member 2|] which is adaptedto'movetoward and from the core bar ll, a coiled spring 2| being connected withthe armature and with the lug 22 carried by the standard l6 servingnormally to swing the armature to the limit of its motion away from thecore bar II.

In the arrangement shown, the coil I9 is connected at one end with thelead 23 of an alternating current circuit comprising said lead and alead 24, being connected at its opposite end with the U member l4 at thepoint 19a. The coil IS in turn is connected at one end with the. corebar I! at the'point lBa and at its opposite end with the base plate iiof the standard II at the point I81), such base plate l2 being providedat one end with a lug 25 having a lead wire 26 electrically connectedthereto. Work devices in the form of lamps 21 are interposed between thelead 26 and the lead 24 whereby such work devices are fed by currentfrom the leads 23 and 24 through said coil l9 and said lead 26. Ashading v tion to thecontacts 30 and 3| as is indicated in core bar IIfor preventing chattering of the ar-' the electromagnet.

- Upon the turned upper end of the standard 1 have mounted a bimetallicarm 29, such arm extending from the standard into position over thearmature 20, the armature and the arm being provided with contactmembers 33 and 3| comprising a switch connection between the armatureand the arm. such switch being arranged in parallel relation to the coilIt so that the switch when closed short-circuits said coil ll. Thearrangement is such that when the switch is closed the current throughthe lead 23 passes through the coil l9, thence through the standard It,the armature 20, the switch comprising the contacts 3|) and 3|, the arm29, the standard II, the lug 25, and the lead 26 to the load devices 21.The coil l9 comprises a fairly small number of turns so that themagnetic field established in the core of the magnet by the currentthrough the coil is insuflicient normally for drawing the armature 20downwardly against the action of the spring 2|. When, however, there isa heavy flux of current through the coil It, by reason of a shortcircuit at the load devices, for example, the strength of the magnet iscorrespondingly increased, and the armature is drawn downwardly servingto open the switch so as to make the coil l3 effective. Under suchcircumstances, with the switch open, the current passes from the lead 23through the coil IS, the core bar H, the coil |8, and out through thelug 25 and lead 26 to the load devices 21. Since the resistance throughthe coil I3 is comparatively great, the current through the coil is keptdown so as to protect the load devices from danger. The number of turnsin the coil I3 is great enough, however, to enable the coils I8 and I9by cooperative action to hold the armature 20 down against the action ofthe spring 2| until the short circuit condition has been corrected.After such correction, as soon as the circuit through the work deviceshas been opened independentlly of the circuit breaker, the armature 20is moved upwardly by the spring 2| and the parts are in condition forrenewed operation.

Upon the outer face of the standard ii of the core member I, .I haveprovided a stop plate 32 insulated by plates 33 from the frame member Atits upper end the stop plate 32 is provided with an arm 34 extendinginto position opposite the outer face of the armature 20 for limitingthe upward movement of the armature, such arm 34 being provided with anotch 35 in its end, the face of which stands in spaced rela- Fig. 5.Above the arm, 28, I have mounted a second bimetallic arm 36, extendingover the arm 29 with a block of insulation 31 interposed between thearms. The arm 23 is arranged so that when it is heated it has a tendencyto curl upwardly away from the armature 23. The arm 36 isreverselyarranged so that when it is heated it has a tendency to curl downwardlytoward the armature. As a result of this arrangement, when the two arms29 and 36 are equally affected by the room temperature they are held inunchanged position since the tendency of one arm to curl is offset bythe tendency of the other arm to curl in the opposite direction. When,however, an overload current is established and maintained for somelittle time through-the arm 29, the arm 23 is heated by the overloadcurrent 2,234,885 coil 23 is mounted upon the upper end of the servingto cause the arm 29 to curl upwardly against the action of the arm 33which is not correspondingly heated since the overload current passesthrough the arm 23 and not through the arm 38. The contact 3| is thusmoved upwardly out of engagement with the contact as is shown in Fig. 4serving to throw the coil l3 into effective operation for drawing thearmature 20 downwardly. The arrangement is such that the armature 20is-held downwardly by the action of the coils i8 and I9 until thecircuit is broken through the work devices 21. When the circuit throughthe work devices is broken after the correction of the overload currentcondition, the

By the use of my improved mechanism, the

circuit is broken Just as effectively as would be done by the melting ofa fuse and the device is brought back to normal condition by the removalof the cause of the short circuit or the overload without the necessityfor the replacement of parts orfor the resetting of any part of themechanism.

While I prefer to, employ the form of device as shown in my drawing andas above described, it is to be understood that my invention is notlimited to the arrangement shown except so far as the claims may be solimited, it being evident that changes might well be made in the formand arrangement of parts without departing from my invention.

I claim:

1. In a circuit breaker, the combination of a core bar, an armaturemovable toward and from said core bar and standing normally in spacedrelation to the core bar, switch means opened by an operative stroke ofsaid armature toward said core bar, a coil on said core bar, circuitmeans connecting said coil and said switch in series, a second coil ofcomparatively much'higher resistance value on said core bar connected inseries with said first-named coil and in parallel arrangement withrespect to said switch means and adapted when the switch means isstanding closed to permit the armature to remain in switch-closedposition and adapted when the switch means has been opened to hold thearmature in switch-opened position, and thermostatically controlledmeans in said circuit means adapted upon the passage of a predeterminedoverload current therethrough to open said circuit means independentlyof movement of said armature.

2. In a circuit breaker, the combination of a core bar, a coil on saidcore bar, an armature movable toward said core barby the influence of anelectric current through said coil, yielding means adapted normally tomove said armature to the limit of its movement away from the core bar,an arm extending into position opposite said armature having a switchingengagement therewith and limiting the outward movement of the armature,stop means limiting the outward movement of the armature independentlyof said arm, circuit means connecting said coil in series with theswitch comprising said arm and said armature, anda second coil ofcomparatively much higher resistance value on said core bar connectedwith said circuit means in parallel arrangement with respect to saidswitch adapted when the switch is standing closed to permit the armatureto remain in switch-closed position and adapted when the switch has beenopened to hold the armature in switch-opened position, said arm beingadapted by movement upon the passage of a predetermined overload currenttherethrough to open said switch independently of movement of thearmature.

3. In a circuit breaker, the combination of a core bar, a coil on saidcore bar, an armature movable toward said core bar by the influence ofan electric current through said coil, yielding means adapted normallyto move said armature to the limit of its movement away from the corebar, an arm extending into position opposite said armature having. aswitching engagement therewith and limiting the outward movementof thearmature, stop means limiting the outward movement of the armatureindependently of said arm, circuit means connecting said coil in serieswith the switch comprising said arm and said armature, and a secondcoilof comparatively much higher resistance value on said core bar connectedwith said circuit means in parallel arrangement withrespect to saidswitch adapted when the switch is standing closed to permit the armatureto remain in switch-closed position and adapted when the switch has beenopened to hold the armature in switch-opened position,

said arm being adapted by movement upon the passage of a predeterminedoverload current therethrough to open said switch independently ofmovement of the armature and adapted when said circuit means is againclosed after the overload condition has been corrected to againestablish normal feed of the current through the switch.

4. In a circuit breaker, the combination of a core bar, a coil on saidcore bar, an armature movable toward said core bar by the influence ofan electric current through said coil, yielding means adapted normallyto move said armature to the limit of its movement away from the corebar, a bimetallic arm extending into position opposite said armaturehaving a switching engagement with the armature and limiting the outwardmovement thereof, stop means limiting the outward movement of thearmature independently of said arm, circuit means connecting said coilin series with the switch comprising said arm and said armature andarranged so that when a predetermined overload current passes throughsaid arm the arm is distorted so as to open said switch independently ofmovement of the armature, and a second coil of comparatively much higherresistance value on said core bar connected with said circuit means inparallel arrangement with respect to said switch adapted when the switchis standing closed to permit the armature to remain in switch-closedposition and adapted when the switch has been opened to hold thearmature in switch-opened position.

5. In a circuit breaker, the combination or a core bar, a coil on saidcore bar, an armature movable toward said core bar by the influence ofan electric circuit through said coil, yielding means adaptednormally tomove said armature to the limit of its movement away from the core bar,a bimetallic arm extending into position opposite said armature having aswitching engagement with the armature and limting the outward movementthereof and adapted upon the heating of the arm to be given a curvaturein the direction away from the armature, a second bimetallic armextending into position opposite said first named arm so as to applypressure on the outer face of said first named arm and adapted upon theheating of said second arm to be given a curvature in the directiontoward said first named arm, stop means limiting the outward movement ofthe armature independently of said arms, circuit means connecting saidcoil in series with the switch comprising said first named arm and saidarmature, said first named arm being adapted by movement upon thepassage of a predetermined overload current therethrough to open saidswitch independently of movement of the armature, and a second coil ofcomparatively much higher resistance value on said core bar connectedwith said circuit means in parallel arrangement with respect to saidswitch adapted when the switch is standing closed with the armaturemoved outwardly with respect to the core bar to permit the armature toremain in such outwardly moved position and adapted when the switch hasbeen opened by the movement of either member of the switch to hold thearmature. moved to the limit of its motion toward the core bar.

6. In a circuit breaker, the combination of core means having two coilsthereon, a movable armature normally in spaced relation to said coremeans and adapted upon a passage of current through one of said coils tomove toward the core means, thermostatic means adapted to have movementupon the passage of an electric current therethrough, and switch meansmechanically connected with and adapted to be opened by movements ofsaid armature and said thermostatic means, one of said coils being elec.

trically in parallel relation with said switch means and the other ofsaid coils being electrically in series relation with said thermostaticed upon the passage of current through one of said coils to move towardsaid core bar against the action of said yielding means, a bimetallicarm, one end of said arm being fixed and the other having movement uponthe passage of cur-- rent through the arm, and switch means comprisingmake and break contact members, one of said contact members being onsaid armature and the other on the movable end of said arm, one of saidcoils being electrically in parallel relation with said switch means,and the other of said coils being electrically in series'relation withsaid arm and said switch means. i

. JOSEPH G. SOLA.

